This study investigates the applicability of time reversal concept in modern acoustics to structural health monitoring. A time reversal method has been adapted to guided-wave propagation to improve the detectability of local defects in composite plate structures. Specifically, wavelet-based signal processing techniques have been developed to enhance the time reversibility of Lamb wave in thin c...

The development of energy harvesting devices with piezoelectric transducers has been widely studied in the last decade. Most of previous studies considered a resonant cantilever beam with an attached tip mass and focused on the proper modeling of the cantilever device, design and optimization of electric harvesting circuit and nonlinear amplification of resonant vibration amplitude. However, fe...

|For crystal resonators, it is always desirable to calculate the electric properties accurately for application purposes. As an extension of the Mindlin plate theory based nite element analysis of crystal resonators, a new theory for the electroded plates is derived and the piezoelectrically forced vibrations are formulated and implemented in this paper in a manner similar to our previous work....

In this paper a new approach is presented to reduce vibrations for oneand two-dimensional mechanical structures, as beam or thin plates, by means of several piezoelectric transducers shunted with a proper electric network system. The governing equations of the whole system are coupled to each other through the direct and converse piezoelectric effect. More in detail, the mechanical equations ar...

Complex analysis of characteristic of underwater noise allows to find several features typical for underwater noise produced by ships as well as correlations between mechanical activity of ship’s mechanism and generated underwater sound. Their vibration activity might be reduced by applying active treatments utilising piezoelectric sensors and actuators. The paper explores the potentials of act...

This paper deals on converting mechanical impact on piezoelectric plate into electrical energy and using this harvested energy to power a wireless sensor node (WSN). Here we discuss on the power processing unit which consists of rectification, storage and regulation of voltage. The wireless sensor node senses the ambient vibrations around it and uses the harvested energy to send unique identifi...

A preliminary study of the feasibility of using piezo-transducer arrays, for detecting flaws in flat aluminum plates and steel tubing, is being performed at The University of Tennessee. The sensor arrays are designed for embedding in aluminum plates and brass tubes. Various forms of defects are placed on the test specimens. Preliminary experiments are carried out using both flat aluminum plate ...

An air-coupled ultrasonic transducer is created by bonding a bulk piezoelectric element onto the surface of a thick plate with a wedge of power-law profile. The wedge is used to improve the ultrasonic radiation efficiency. The power-law profile provides a smooth, impedance-matching transition for the mechanical energy to be transferred from the thick plate to the air, through the large-amplitud...

The validity of the dynamic analysis based on simplified plate model was investigated using of FE-codes ANSYS in the present paper. The simplified clamped multilayered plate model was first verified by comparison with the exact model. The simply supported plate model was confirmed to be not a suitable model due to its large error as comparing with exact model. Influence of dimensions of lamina...

This study used the commercial CFD software ANSYS CFD / Fluent, for simulating the transient flow field and investigating the radiator heat effects of radiator for single piezoelectric fan in a single rectangular flow channel, respectively, for two kinds of heat devices, which were flat and square columnar types placed horizontally or vertically in order to find the optimum cooling radiator pos...